Mechanisms of Gene Regulation
Fauver, N. A. , Goeres, D. C. , Zhang, W. , Sieburth, Leslie E. .
Phenotypic Consequences of mRNA decapping defects in Arabidopsis are suppressed by URSULA.
A study of vascular mutants in Arabidopsis revealed a critical role for mRNA decapping in early seedling development. The trident (tdt) mutant shows numerous vascular patterning defects, and TDT encodes the mRNA decapping enzyme. The phenotypic severity of tdt mutants, however, depends on the plant’s genetic background; mutants in Col-0 produce no leaves and have severe vascular defects, whereas after introgression into L.er, the tdt (L.er) mutants are partially suppressed, and have modestly-sized leaves and fewer vascular defects. Our data indicate that an unlinked locus in L.er suppresses the tdt phenotype, and we have named this suppressor URSULA (URS). The goal of this study is to understand the molecular basis for URS suppression. Decapping initiates the 5’ to 3’ RNA decay pathway, and occurs in cytoplasmic particles called P-bodies. An alternative bulk mRNA decay pathway initiates at the mRNA’s 3’ end, proceeds in a 3’-to-5’ direction, and is carried out by the exosome. Models for phenotypic suppression of the tdt decapping mutant include: (1) URS could enhance mRNA decay from the 3’ end or (2) URS could partially restore either decapping or P-body formation. To distinguish between these, and alternative models for URS function, we are using three approaches. First, we are working to characterize URS molecularly. We are using map-based strategies, and have defined an interval on chromosome 3 that contains the URS gene. Second, we are comparing the levels of accumulated mRNAs in tdt mutants in Col-0 and L.er backgrounds and are comparing the mRNA decay kinetics for specific mRNAs in wild type (L.er , Col-0) and tdt mutants (Col-0 and L.er backgrounds). Finally, we are using GFP fusion proteins to assess whether P-bodies can form in partially suppressed tdt mutants.
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1 - University of Utah, Biology, 257 South 1400 East, Salt Lake City, UT, 84102, United States
2 - University of Utah, Biology
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM